The Periodic Table of the Elements is undoubtedly the most elegant organizational chart ever devised. This chart is organized to show the relationships among chemical elements with similar characteristics. This chart facilitates an understanding and prediction of the properties of the elements and how they react with each other to form hundreds of thousands of compounds. A sample conventional Periodic Table of the Elements is shown in FIG. 1. Another sample conventional uninterrupted rectangular Periodic Table of the Elements is shown in FIG. 2.
At present, the Periodic Table is represented in most books and charts in a rectangular form. Periods are the rows that run from left to right. Both the atomic numbers (number of protons) and electrons increase in number from left to right in each Period. The vertical columns represent families of elements that exhibit similar characteristics. These families are called Groups. Elements in the same Group, in general, exhibit similar combining powers (valence), but do not exhibit the same degree of reactivity to other elements.
In 1996, the International Union of Pure and Applied Chemistry (IUPAC) introduced a new notation system of arabic numerals, 1 to 18 for Groups in the s-, p-, and d-Blocks. By this convention, the 14 f-Block elements are not assigned to any Groups. When a principal energy level (shell) receives its full complement of electrons, e.g., inert gases in Group 18 (8A), a new row begins, which is the start of a new Period. For instance, lithium is located at the start of Period 2 and has 1 electron in its outer shell as in Group 1 (1A), and neon, located at the end of Period 2 in Group 18 (8A), has 8 electrons in its completed shell.
The Periodic Table is divided into the following Blocks based on the electron configurations of the elements. These Blocks form large families and the number of elements in each Block is computed by calculating the product of the rows (Periods) and columns (Groups) that make up the Block. Period 1 has only two elements and represents a unique situation. Both hydrogen (1H) and helium (2He) have s-electrons, but helium has a complete outer shell and should be grouped with the other inert gases in Group 18. Therefore, helium can occupy any of the two positions in the Periodic Table. For purposes of calculating the number of elements in the various Blocks, helium will be placed in Group 2 as part of the s-Block. The total number of elements in the Periodic Table can be derived from the following calculation:
Periods (rows) × Groups (columns) = Number of elements in a Blocks-Block(7 rows × 2 columns) =14 elementsp-Block(6 rows × 6 columns) =36 elementsd-Block(4 rows × 10 columns) =40 elementsf-Block(2 rows × 14 columns) =28 elementsAnd the total possible elements for 7 complete Periods is 118 elements.
The transition elements are found in three series in the center of the Periodic Table starting with Group 3. The first series is in Period 4, from scandium (21) to zinc (30). The second series is in Period 5, from yttrium (39) to cadmium (48). The third series found in Period 6 is a bit different. It starts at Group 4 at the element lanthanum (57) and continues to include mercury (80). But the building-up of the series is interrupted immediately after lanthanum by a transition series within a transition series, that is, an inner transition series. The inner series consists of the 14 f-block, rare-earth metals or lanthanides, beginning with cerium (58) and ending with lutetium (71). The transition series therefore begins with lanthanum (57) and ends with mercury (80) to comprise the d-block elements. Similarly, the fourth series occupies the same relative position in Period 7. This transition series begins with actinium (89) and ends with ununbiium (112), but is interrupted immediately after actinium by the 14 inner-transition elements thorium (90) to lawrencium (103) spliced in between. Currently, the inner-transition blocks appear separately in most conventional books and charts. While the conventional Periodic Table of the Elements is elegant, it is possible that a different presentation can facilitate a better understanding of the elements.